1. The Field of the Invention
This invention relates to novel, improved processes and apparatus for producing cutting surfaces for cutting instruments. More particularly, the present invention relates to novel, improved processes and apparatus for producing razor blades and the like.
2. Description of the Prior Art
Presently, razor blades are produced by way of continuous, high-speed mass production techniques involving a plurality of sequential abrading operations to provide the cutting surface including the cutting edge. Each abrading operation provides a facet on opposed surfaces of the cutting surface and the facet may or may not be modified by subsequent abrading operations. Normally, at least three abrading operations are required to provide the facets defining the cutting surface of the finished razor blade. The first operation is the grinding operation and involves abrading opposed surfaces of a continuous sheet of metal to provide a first or "ground" facet on opposed surfaces. Thereafter the metal sheet is subjected to a rough honing operation to provide a second facet or "rough honed facet" on the surfaces while a finish honing operation provides the cutting edge facets for opposed edge surfaces of the blade. Additional details relating to present commercial razor blade manufacturing processes and apparatus can be found in commonly owned U.S. Pat. No. 3,461,616. As disclosed there, a continuous metal strip is subjected to a grinding operation, a rough honing operation and a final honing operation which provides a convex cutting edge. U.S. Pat. No. 3,461,616 is expressly incorporated herein in its entirety by reference.
The processes and apparatus disclosed in U.S. Pat. No. 3,461,616 represent a significant advance in the high-speed, continuous manufacture of razor blades. Essentially, the disclosed processes and apparatus include the three conventional abrading operations, i.e., the grinding, rough honing and finish honing operations. In the grinding operation, one of the opposed edge surfaces of a strip of blade metal is abraded first while the other opposed surface is abraded later to provide the ground facet of the cutting surface. In both the rough and finish honing operations, the opposed surfaces are abraded substantially simultaneously since the abrading means involved includes two juxtaposed abrading wheels. The novel and distinctive feature presented in the processes and apparatus of U.S. Pat. No. 3,461,616 involves the finish honing operation. In this operation, the opposed surfaces of the blade's cutting surface providing the cutting edge is abraded with abrading means arranged and adapted to initially abrade opposed edge surfaces at a relatively high included angle and thereafter abrade the opposed edge surfaces at progressively decreasing included angles to provide curved, convex cutting edge facets on the opposed surfaces. The finish honing operation of U.S. Pat. No. 3,461,616 provides several distinct advantages in commercial razor blade manufacturing processes. The most significant advantage involves the achievement of an increase in the production rate of razor blades by about five or more times.
In the processes and apparatus of U.S. Pat. No. 3,461,616, the grinding operation has been found to be a factor having an effect on the overall efficiency of the production process. Oftentimes, the grinding operation leaves a residual wire or burr at the edge of the ground surface and removal of the wire increases wear of the abrading surfaces in the entry region of the abrading means providing the rough honed facet. Additionally, automatic monitoring and adjusting means are normally arranged between the grinding and rough honing stations to detect irregularities in the ground facets and to signal appropriate adjustments to the grind station to compensate for detected irregularities. The monitoring and adjustment means are expensive, highly sophisticated and can have a limiting effect on the production rate. Accordingly, although the processes and apparatus of U.S. Pat. No. 3,461,616 are highly efficient and cost effective, there still remains a need in the art for processes and apparatus providing maximized efficiency and cost effectiveness in the mass volume production of razor blades having high quality performance characteristics. The present invention is addressed to that need and provides an extremely effective response to it.